On 8/8/2018 10:46 AM, Bruno Marchal wrote:
On 8 Aug 2018, at 13:50, Bruce Kellett <bhkell...@optusnet.com.au
<mailto:bhkell...@optusnet.com.au>> wrote:
From: *Bruno Marchal* <marc...@ulb.ac.be <mailto:marc...@ulb.ac.be>>
On 8 Aug 2018, at 01:39, Bruce Kellett <bhkell...@optusnet.com.au
<mailto:bhkell...@optusnet.com.au>> wrote:
From: *Bruno Marchal* <marc...@ulb.ac.be <mailto:marc...@ulb.ac.be>>
If there is a FTL physical influence, even if there is no
information transfer possible, it leads to big problems with any
reality interpretation of special relativity, notably well
described by Maudlin. Maudlin agrees that many-mind restore
locality, and its “many-mind” theory is close to what I think
Everett had in mind, and is close to what I defended already from
the mechanist hypothesis. To be sure, Albert and Lower Many-Minds
assumes an infinity of mind for one body, where in mechanism we
got an infinity of relative body for one mind, but the key issue
is that all measurement outcomes belongs to some mind. The
measurement splits locally the observers, and propagate at
subliminal speed.
I don't think that the many-minds interpretation is really what you
would want to support. In many-minds, the physical body is always
in the superposition of all possible results, but the 'mind' can
never be in such a superposition,
That sides with Mechanism. In arithmetic there is an infinity of
identical (at the relevant representation level) brains. Now Albert
and Loewer seems to associate an infinity of mind with one body.
The 'infinity of minds for each body' was postulated by Albert and
Lowe to avoid the 'mindless hulk' problem. In other words, it was
just an /ad hoc/ fix for a problem in the theory. This alone should
have been sufficient to render the theory unacceptable.
I agree. That is why I remain closer to Everett. This problem is
automatically solved with Mechanism. There is no empty hulk, given
that there is no hulk.
I do not understand this, and with the Mechanist “many-dreams” it is
the contrary: each mind as an infinity of (virtual) bodies, and the
consciousness will differentiate along their computational different
continuations. Take the WM-duplication. After the reconstitution,
but before the copies open the door, one mind is associated to two
bodies, and then differentiates in W or in M from each location
perspective. To say that the mind is not in a superposition is
equivalent with Everett’s justification that the observer cannot
feel the split, and it is where Everett use (more or less
explicitly) the mechanist hypothesis.
The splitting in Everett's theory at least makes some sort of sense,
and is not postulated /ad hoc/.
I agree.
The real problem I see with many-minds theory is that it does not
actually explain the observed correlations. The correlations are
presumed not to exist in reality -- all possible combinations of
experimental outcomes happen, but when Alice and Bob meet, their
bodies are still in indefinite states -- no actual results are
recorded by entanglement with their bodies -- but their minds will be
in definite states that agree with the quantum correlations. This
step seems to introduce yet more unreasonable magic into the
'explanation'. Why are the minds like this when they communicate?
Because all Alice and Bob are coupled in that way, by the singlet
state. That works if we keep in mind that the singlet state (when not
already observed by neither Alice nor Bob) describes an infinity of
Alice and Bob,
What does that mean? Alice chooses a measurement axis and Bob chooses a
measurement axis. That's two. Where does the "infinity" come from?
Are you postulating a multiverse in which all possible measurement axes
are chosen by ensembles of Alices and Bobs?
Brent
with the spin in all directions, but always correlated. When Alice and
Bob make their measurement, if they are space separated, it makes no
sense to ask if they are or not in the same world or branches. The
result they obtained only entangle each of them with the environment,
locally, and that spread on the whole universe (at subliminal speed)
so that both of them will encounter only their “correlated” counterparts.
Especially since there are pairs of observers who get results that do
not agree with QM (the 'mindless hulks!’).
Alice and Bob always get results which confirms QM. But when they are
space-like separated, their consciousness will only be able to
differentiate into histories which contains the correlation.
Maudlin moved on in the years between the first edition of his book
in 1994 and the third edition in 2011.
You told me. Maudlin is very good, but is not a fan of Everett, nor
even of Mechanism. He argued also, and independently of me, that it
makes no sense to keep both mechanism and materialism. The end of his
paper “Computation and Consciousness” (Journal of Philosophy, 1989)
suggests he is more willing to keep Materialism instead of Mechanism.
I show that indeed the mechanist solution generalises Everett on the
whole (sigma_1, semicomputable) part of the arithmetical
reality/truth. I reduce the mind-body problem to the problem of
recovering physics from a statistics on first person experience in
arithmetic (where there is no hulk, nor need of hulk).
In his 2011 thinking I can only imagine that he would have seen
many-minds in much the same way as he later saw many-worlds -- if
appeal is made to the wave function to make sense of the correlations
in many-worlds, then we have to recognize that this is not a /local/
account since the wave function is not a local object.
I don’t really understand what you mean by that. I am reading your
paper, which is nice and well written, but too quick for me on both
Tipler and Baylock. It helps me to better see how you interpret the
wave, and where we might differ.
It seems to me that when Alice and Bob prepare the singlet state, even
before their long distance separation, there is no sense to say that
they are still in the same world. They are only because their interact
and entangle and re-entangle very quickly, but still always at light
speed or slower. But even if there is only one cm between Alice and
Bob, it makes no sense to say that they are in the same world. They
might find uncorrelated results, but, at the speed of alight, each one
will only be able to talk to its correctly correlated counterparts.
The same can clearly be said of the many-minds approach.
The wave function is not local because the entangled singlet state is
non-separable.
OK.
Non-separability means that if you interact with one part of the
state, you affect the whole state:
I am not sure you affect any state. You just discover in which branch
you are. The wave only described a multiplicity of realties(available
history), and in this case, when someone, Alice say, look at
something inseparable, she got information about her branche(s), and
of course she knows that any possible future Bob will have the
correlated result. But Bob, if space-separated, might very well find a
non correlated result, which means that he localised itself in another
branch, where him too will only be able to meet his corresponding
correctly correlated Alice.
That is how I interpret the QM wave, or the Heisenberg matrices. I am
afraid that a “real” treatment would need a quantum theory of space
itself, but this needs a solution to the quantum gravity problem.
the state cannot be split into separate non-interacting parts, one
for each particle in the singlet.
I agree with this. But that can be interpreted by the fact that we are
ignorant in which branch we are. Being in the same branch is an
equivalence relation on the object with which we can interact with,
and space separation entails that the measurement are truly
uncorrelated “in the absolute”, yet all the Alices and Bobs couples
localises themselves in the branches violating the Bell’s inequality.
Alice would need to go quicker than the speed of light to see some Bob
finding an uncorrelated result, like overpassing the decoherence time.
That is why the non-locality is unavoidable -- in many minds as in
many-worlds -- it is an intrinsic part of quantum theory, and is
perhaps the most significant way in which quantum mechanics differs
from classical mechanics (you don't get non-separable states in
classical mechanics, although you do get interference between
classical waves).
I agree with all this, but the many-worlds, or the relative states
explains this without a physical action acting FTL. It is very special
indeed, as the confirmation of that Bell’s Inequality violation
confirms that LOCALITY + DETERMINACY (+ some amount of physical
realism) makes the Relative States existence obligatory.
Which of course I find nice, as it makes QM looking exactly like a
solution of the Mechanist Mind-body problem, where the physical body
can be shown to make sense only through a statistics on all
computational states (structured by self-referential correctness).
so stochastically chooses to record only one definite result from
the mix. In the Wikipedia article on the many-minds interpretation,
the following comment might be relevant for you:
"Finally, [many-minds] supposes that there is some physical
distinction between a conscious observer and a non-conscious
measuring device, so it seems to require eliminating thestrong
Church–Turing hypothesis
<https://en.wikipedia.org/wiki/Church%E2%80%93Turing_thesis#Philosophical_implications>or
postulating a physical model for consciousness.”
What does they mean by “Strong Church-Turing hypothesis”?
I imagine that the Wikipedia author means that the strong CT
hypothesis supposes that the world is nothing more than a computation.
STRONG CT would be Digital Physicalism. This has been refuted since
long, if by world we mean the physical world. If my local body is
Turing emulable (with consciousness preservation), then physics is
reduced to a statistics on all computations, which can be shown to
have non computable elements.
The physical reality can be very well approximated by a computation,
but in the limit (where the first person lives) it cannot be
computable. To make some measurement and get all correct decimal in a
theory for that measurement, you need to execute the whole universal
dovetailing in an instant, which is impossible.
That makes no sense. The UD is operating in Platonia, not in Einstein's
spacetime. "An instant" is a derivative, computed, concept in the
output of the UD.
Brent
Mechanism makes also matter trivially not clonable. You cannot clone
your infinite ignorance about which computations execute you.
The above sentence does not make sense. The many-worlds theory is a
direct consequence of the SWE + the mechanist theory theory of mind.
It is the collapse of the wave which would be threat to Mechanism
(and of Rationalism).
If machines can do something that the mind cannot do (viz., be in a
superposition of all possible results, when the mind cannot
participate in any such superposition),
The mind cannot NOT participate to the infinite superposition which
is not eliminable from arithmetic. That is why we have an infinity
of body in arithmetic, and why when we look closely to the
environment, i.e. below our mechanist substitution level, we must
find the sign of the presence of the alternate computations, like
QM-without-collapse confirmed.
So, contrary to what you said above, you do not really agree that the
supposedly local 'many-minds' account given by Maudlin in his book is
close to what you think?
You can say that. Maudlin saw that the Many-Mind theory is local (at
least in his 2009 book, I will buy the 2011 soon or later) but he
surimposed a “one world” structure, which leads to empty hulk and
zombie and to an infinity of mind for one body, which makes not much
sense. I think all this comes from too much naive notion of mind and
world. With computationalism we get the opposite: each mind get
associated with an infinity of relative computational states, the
different modes (true, believable, knowable, observable, sensible)
result from the incompleteness of all universal theories.
the Church-Turing thesis goes out the window -- and you might not
want to say "Yes, Doctor".
I think the complete opposite of this is correct. Church’s thesis go
hand in hand with the non collapse (and non guiding potential) of
the quantum wave. The only problem that Everett missed, is that, for
all this to be consistent, extract the formalism of the Wave itself
from the statistic on all computations. Then the logic of machine
self-reference and its variants imposed by incompleteness gives the
complete solution at the propositional level, and that works, in the
sense that we get quantum logic where we should, making Mechanism
not (yet) refuted by observations.
But that is your theory of mechanism, which is not to be found in
quantum theory at all.
Everett use Mechanism. Darwin uses Mechanism. Diderot defined
rationalism by Mechanism, and when Milinda ask to Arjuna what Arjuna
is, Arjuna explained what a machine is.
It is not my theory of Mechanism. It is a very old idea. Then
Incompleteness, which is a one-diagonalization consequence of the
Church-Turing, shows that we are quite ignorant of what machine can
and cannot do, and the execution of all computations in arithmetic
invites us by itself to doubt physicalism. There is a non physical
reason for the physical laws: they emerge from the logic of what the
average universal machine (an arithmetical notion) can bet to live
from its first person perspective.
There is a many-dreams interpretation of arithmetic/combinator, and
all universal number/combinator converges to it.
And if that differ from the observations, it will be time to invoke
magical things like primary matter or spooky action at a distance, or
elves and gods and other actual infinities. But then I need strong
evidence, and a departure of Nature from the machine’s observable mode
might be such. But up to now, nature seems to obey the laws of the
universal machine dreams.
Bruno
Bruce
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